The most immediate opportunity for this system is to assist NASA in the development of next generation quiet aircraft, including conventioanl tube and wing (current generation "N"+1), unconventional integrated airframe-propulsion system configurations (N+2), and advanced aircraft concepts (N+3). These aircraft are likely to have noise levels from the engine and airframe that are comparable. A deployable, quiet air-brake device will allow noise reduction by creating drag without the associated unsteady flow structures of devices such as flaps, slats, and undercarriage. In addition, these devices will enable steep approaches, thereby locating the noise source further from the affected communities. Finally, pairs of engine air-brakes operating in concert on multi-engine aircraft may be used for aircraft control and special maneuvering applications by performing, for example, an aircraft rudder function. An additional application for swirling exhaust flows is in the area of wake vortex avoidance and induced drag management. For example, deployable swirling outflow devices placed on wing tips could be used to counter- or co-swirl relative to the bound vortex that is shed by a finite wing, resulting in potential induced drag reduction or increase (possibly of value in a quiet drag sense). This could prove to have some applicability in designing more fuel-efficient and quiet aircraft in the future. Two complementary potential commercial markets exist for the proposed technology: (1) implementation in retrofit kits on older aircraft engines, and (2) implementation in future jet engines as an integral part of the design; i.e., modifying traditional engine exit guide vanes or bypass nozzles with a variable geometry mechanism that generates a swirling outflow in drag management mode. The first market has immediate potential (within 5 years), while the second market, although potentially much larger from a quantity standpoint, is a longer-term endeavor (likely 7 to 10 years to implementation). The retrofit market provides a simpler and faster opportunity to implement and demonstrate the technology before upselling it or its derivatives to the large engine Original Equipment Manufacturers. As part of this SBIR program, ATA will partner with small engine manufacturer Williams International to understand how the design may be incorporated into one or more of their engines. As the world leader in the development, manufacture, and support of small gas turbine engines, Williams International provides a more direct route to market for the technology than could be achieved with the large aircraft engine manufacturers where the financial and technical risks of new technologies grow exponentially. Demonstration on a real-world, small jet engine can provide a stepping stone to wider acceptance of the technology in the gas turbine engine community.
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